From 14affd8ffa601b52ba49127ae674d3aa139da756 Mon Sep 17 00:00:00 2001
From: "J.D. Purcell" <jdpurcell@gmail.com>
Date: Sat, 22 Mar 2025 17:14:38 -0400
Subject: [PATCH] Optimize LZMA range decoder

---
 .../Compressors/LZMA/RangeCoder/RangeCoder.cs     |  2 ++
 .../Compressors/LZMA/RangeCoder/RangeCoderBit.cs  | 15 ++-------------
 2 files changed, 4 insertions(+), 13 deletions(-)

diff --git a/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoder.cs b/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoder.cs
index 87906809..23b3b0b9 100644
--- a/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoder.cs
+++ b/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoder.cs
@@ -1,6 +1,7 @@
 #nullable disable
 
 using System.IO;
+using System.Runtime.CompilerServices;
 
 namespace SharpCompress.Compressors.LZMA.RangeCoder;
 
@@ -152,6 +153,7 @@ internal class Decoder
         }
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public void Normalize2()
     {
         if (_range < K_TOP_VALUE)
diff --git a/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoderBit.cs b/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoderBit.cs
index dd93b526..562b2356 100644
--- a/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoderBit.cs
+++ b/src/SharpCompress/Compressors/LZMA/RangeCoder/RangeCoderBit.cs
@@ -107,24 +107,13 @@ internal struct BitDecoder
         {
             rangeDecoder._range = newBound;
             _prob += (K_BIT_MODEL_TOTAL - _prob) >> K_NUM_MOVE_BITS;
-            if (rangeDecoder._range < Decoder.K_TOP_VALUE)
-            {
-                rangeDecoder._code =
-                    (rangeDecoder._code << 8) | (byte)rangeDecoder._stream.ReadByte();
-                rangeDecoder._range <<= 8;
-                rangeDecoder._total++;
-            }
+            rangeDecoder.Normalize2();
             return 0;
         }
         rangeDecoder._range -= newBound;
         rangeDecoder._code -= newBound;
         _prob -= (_prob) >> K_NUM_MOVE_BITS;
-        if (rangeDecoder._range < Decoder.K_TOP_VALUE)
-        {
-            rangeDecoder._code = (rangeDecoder._code << 8) | (byte)rangeDecoder._stream.ReadByte();
-            rangeDecoder._range <<= 8;
-            rangeDecoder._total++;
-        }
+        rangeDecoder.Normalize2();
         return 1;
     }
 }